Device for regenerating printed sheet-like recording medium

ABSTRACT

The present invention discloses a device for regenerating a sheet-like recording medium comprising a means for feeding a printed sheet-like recording medium, a regenerating treatment means having a step for eliminating image formed on said recording medium, a means for discriminating and separating the recording medium whether the treated recording medium is reusable or not and a means for storing the separated reusable recording medium. 
     Further, the present invention discloses, as Examples, regenerating treatment means treating sheet-like recording media printed with following toners or inks with following degrading agent or a color eliminating agent; 
     (i) a toner comprising biodegradable plastics as a constituent ingredient and an enzyme containing liquid as a degrading agent; 
     (ii) a toner comprising photodegradable plastics as a constituent ingredient and an irradiation of a light containing a short wavelength light; 
     (iii) a toner or an ink using a coloring material comprising an electron-donating color-forming organic compound and its developer and a color-eliminating agent; and 
     (iv) a toner or an ink using a coloring material comprising an electron-accepting color-forming organic compound and its developer and a color-eliminating agent.

BACKGROUND OF THE INVENTION

The present invention concerns a device for regenerating a printedsheet-like recording medium for erasing images on a printed sheet-likerecording medium and enabling the thus treated medium to be reused as itis by a printing device.

Recently, amount of recording paper used in individual firm ororganization has been greatly increased along with the startlingprogress in copying machines and word processors which has,correspondingly, increased the amount of printed paper to be discarded,and regeneration and reuse thereof has become a significant problem inview of environmental protection.

For regenerating such paper, although it has been adapted to beat theprinted paper into pulpous form, which is then formed by a paper-makingprocess into paper for reuse in a very small amount, it requires topreviously discriminate as to whether or not the printed paper can bedeinked after pulping. However, while the discrimination generally needsan expert's judgment, it is difficult to leave the judgment of thedeinking property to outside experts in view of keeping the contents ofthe recording paper to be discarded in secret. From a view point ofkeeping secret, discarded documents are finely shredded by cutters suchas shredders before disposal in most of firms or organizations. However,it is actually impossible to separate such shredded recording papers tobe discarded into those which can and can not be deinked and, inaddition, to remove clips or plastic materials included therein, andthey are after all put to incinerating treatment at present. Thisinvites reckless deforestation and also leads to air pollution.

Further, even when it is attempted to prepare regenerated paper bydeinking the thus shredded recording papers and putting them to apaper-making step, since the resultant regenerated paper has a dark toneand the cost for the regeneration is more expensive than that for theproduction of new papers, it is not favored both by consumers andmanufactures and only little amount of the printed paper is utilized forthe regeneration at present.

The present inventors have made an earnest study for completing aregeneration device for a printed sheet-like recording medium capable ofdissolving the foregoing problems, aiming at regeneration device capableof treating the medium at least in each of firms or organizations, ifpossible, in a restricted quarter, i.e., a regeneration device that canbe used with ease and convenient like that existing copying machineswith a view point of keeping secret and, as a result, have accomplishedthe regeneration device of the present invention in an approach oferasing images on the printed sheet-like recording medium and restoringit into the original state.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a device forregenerating printed sheet-like recording medium.

Another object of the present invention is to provide a device forregenerating a printed sheet-like recording medium that can be used withease requiring no skilled knowledge of experts.

A further object of the present invention is to provide a device forregenerating a printed sheet-like recording medium capable of treatingthe printed recording medium, which is otherwise a waste, withoutleaking its secret contents to the outside, in a restricted inside orquarter and capable of using it as a new recording medium.

A further object of the present invention is to provide a device forregenerating a printed sheet-like recording medium comprising means forsupplying a sheet-like recording medium, means for applying regeneratingtreatment, means for separation and means for storage.

A further object of the present invention is to provide a device forregenerating a printed recording medium comprising means for applyingregenerating treatment by treating the printed surface of the sheet-likerecording medium printed with a degradable toner by means of a degradingagent containing an enzyme or an enzymatically effecting material, orunder the irradiation of a short wavelength light thereby erasing imagesthereon.

A still further object of the present invention is to provide a devicefor regenerating a printed recording medium comprising a regenerationtreating means for treating the printed surface printed with a toner orink comprising an electron donating or electron accepting color-formingorganic compound and a color developer as a coloring material with acolor-eliminating agent, thereby erasing images thereon.

BRIEF EXPLANATION OF THE DRAWINGS

FIG. 1 is a schematic view illustrating the arrangement of an entireconstitution of a regeneration device according to the presentinvention.

FIG. 2 is a schematic view for the arrangement of a control section inthe regeneration device according to the present invention not shown inFIG. 1.

FIG. 3 is a graph illustrating a relationship between the detectionoutput of a density detection element and the amount of a residual tonerused for the control section shown in FIG. 2.

FIG. 4 is a schematic view for the arrangement of an improvedregeneration device according to the present invention which comparesthe printed density on a printed sheet-like recording medium beforeregenerating treatment and a printed density after the regeneratingtreatment and separating the treated medium into those that arereusable, those that are not reusable and those to be recycled to theregenerating treatment means.

FIG. 5 is a schematic view for the arrangement of a control sectioncoping with an increase of one separating and conveying circuit for thetreated medium in FIG. 4.

FIG. 6b shows scanning lines on the printed surface of the sheet-likemedium in which the density detection element is made movable to rightand left as is shown in FIG. 6a.

FIG. 7a is a flow diagram illustrating the conveying path for thesheet-like medium in the regeneration device shown in FIG. 4 and theswitching operation therein.

FIG. 7b is a flow diagram illustrating a case instructing a part to beerased on a displayed image as are described with FIGS. 12 and 13.

FIG. 8 shows a print degrading treatment section constituting theregenerating treatment means in the regeneration device for a recordingmedium printed by a biodegradable toner and a drying section and FIG. 9shows a cleaning section also constituting the means described above.

FIG. 10 shows a print degrading treatment section and a cleaning sectionconstituting the regenerating treatment means in the regeneration devicefor the recording medium printed by a photo-degradable toner.

FIG. 11 shows a print degrading treatment section and a drying sectionconstituting the regenerating treatment means in the regeneration devicefor the recording medium printed by using a toner or ink comprising anelectron donating or electron accepting color-forming organic compoundand a developer as a coloring material.

FIG. 12 shows a constitution of using a color-eliminating agent jettingnozzle that moves within a plane in parallel to a surface of therecording medium and in the direction perpendicular to the mediumproceeding direction (that is, right and left direction) in the printdegrading treatment section, and disposing a detection section fordetecting the deposition range and the density of the toner or the inkon the medium before the treatment section.

FIG. 13 shows a constitution of a control section in the regenerationdevice having the print degrading treatment section and the detectingsection shown in FIG. 12.

Meanings for the references (including numericals) used in each of thefigures are shown below.

S: Printed sheet-like recording medium

1: 1A: Housing for the entire regeneration device

2: Means for feeding sheet-like recording medium

2A: Printed sheet-like recording medium containing tray

2B: Delivery roller

3: Regenerating treatment means

3A: Print degrading treatment section

3A1 Introduction port

3A2 Discharge port

3A3 Degrading agent storage tank

3A4 Degrading agent coating member

3A5 Conveyor belt

3A6 Driving pulley

3A7 Driven pulley

3A8 Temperature/humidity sensor

3A9 Ultrasonic humidifier

3A10 Ceramic heater

3A11 Light irradiation member

3B: Drying section

3B1 Conveyor belt

3B2 Heater

3B3 Blower

3B4 Duct

3C: Cleaning section

3C1 Toner removing member

3C2 Ultrasonic vibrator

3C3 Cleaning member

3C4 Toner recovering member

4: Separation means

4A: Density detecting element

4B: Separating section

4B1 Conveyor belt (effective length: L)

4B2 Conveyor path switching pawl

4B3 Change-over switch

4B3a Driving circuit

9: Storage means

9A: Reusable recording medium discharging channel

9A1 Reusable recording medium tray

9B: Not-reusable recording medium discharging channel

9B1 Not-reusable recording medium tray

5: FIG. 11

5A: Print degrading treatment section

5A1 Color eliminating agent tank

5A2 Color eliminating agent coating device

5A4 Coating felt

5A5 Coating roller

5A5a Roller driving motor

5A3 Color-eliminating agent recovery apparatus

5A6 Driven roller

5A7 Scraper

5A8 Agent recovery tank

5B: Drying section

5B1 Conveyor belt

5B2 Lower heater

5B3 Upper heater

1: Regeneration device (FIG. 4)

1B: Sheet-like recording medium feeding means

1B1 Storage cassette

1B2 Delivery roller

1B3 Feed roller

1C: Regenerating treatment means

1D: Storage means for regenerated sheet-like recording medium

1D1 Reusable medium stacker

1D2 Not reusable medium disposal tank

1D3 Shredder

1E: Separating means

1E1 Treated paper conveying path

1E1a Switching pawl for not reusable medium conveying path

1E1b 1E1a driving solenoid

1E1c 1E1b driving circuit (FIG. 5)

1E2 Reusable recording medium conveying path

1E2a Conveying passage switching pawl for medium to be recycled to 1C

1E2b 1E2a driving change-over switch

1E2c 1E2b driving circuit (FIG. 5)

1E3 Not reusable medium conveying path

1E4 Recycling conveying path to 1C

3 & 4: Printing density detecting elements

6: Detecting section (FIG. 12)

6A: Charge-coupled device

6B: Density detecting element

6C: Pinch roller

7: Print degrading treatment section (FIG. 12)

7A: Spray head

7A1 Rod

7A2 Pulley

7A3 Endless belt

7A4 Nozzle moving motor

7A4a 7A4 driving circuit (FIG. 13)

7A5 Color-eliminating agent tank [incorporating pump 7A5′ (not shown)]

7A5′a 7A5′ driving circuit (FIG. 13)

7B: Recording medium and detecting element

7C: Pinch roller

7D: Guide plate

7E: Conveyor belt

8: Control section (FIGS. 2, 5 and 13)

8A: Microcomputer

8B: Input/output (I/O) interface

8C: RAM

8D: ROM

DETAILED EXPLANATION OF THE INVENTION

The sheet-like recording medium referred in the present inventioninvolves all sheet-like media capable of recording by printing, forexample, paper, plastic sheet, cloth and sheet-like non woven fabric.The term “recording paper” or “paper” to be described hereinafter in thepresent specification means such sheet-like recording media as describedabove unless otherwise specified.

The present invention is a device comprising a means for feedingrecording paper after printed with a printing apparatus, a regeneratingtreatment means having a step of erasing images formed on the printedpaper, a means for detecting, discriminating whether the regeneratedrecording paper can be reused or not, and separating the recording paperaccording to the detection and a means to stock the separated reusablerecording paper.

Further, in accordance with the present invention, the regeneratingtreatment means comprises a print degrading treatment section, a drivingsection and a cleaning section.

Further, in the regeneration device of the present invention comprisinga means for feeding printed recording paper, a regenerating treatmentmeans having a step of erasing images formed on the printed paper, ameans for detecting, discriminating whether or not the regeneratedrecording paper is reusable and, separating the paper according to thediscrimination and a means to store the separated reusable recordingpaper, it is preferable that at least the print degrading treatmentsection, for erasing print, in the regenerating means can be tightlyclosed.

Further, in the regenerating treatment means of the present inventioncomprising at least a print degrading treatment section and a drivingsection for driving the print degraded recording paper, it is preferablethat the drying section can be tightly closed.

EXAMPLE

Description will be made in details with the examples of the presentinvention referring to FIG. 1 to FIG. 13.

As seen in FIG. 1, the regeneration device according to the presentinvention comprises a paper feed means 2 using an optional known method,a regenerating treatment means 3 the content of which is to be describedlater, a separating means 4 for (which can include, for example, theelements shown at 4A and 4B) detecting the printed density on thesurface of regenerated paper, discriminating whether the paper isreusable or not and separating the same in accordance with thediscrimination and a storage means 9 (which can include one or more binsas shown at 9A, 9A1, 9B1, etc.) for storing the separated paper intoeach of stuckers.

Further, it is preferable to connect the regeneration device to aprinting apparatus, for example, by placing a printing apparatus, suchas a copying machine, (e.g., as shown at 100 in FIG. 1) on the uppersurface of the housing 1A.

The paper feed means 2 comprises a containing tray 2A and a deliveryroller 2B for the printed recording paper to be regenerated.

In the separation means 4, a printed density on the paper after theregenerating treatment by a printed density detecting element 4A, suchas a photosensor, a detected output thereof is input via an input/outputinterface 8B of a control section 8 in FIG. 2 to a microcomputer 8A.

In 8A, it is judged whether the regenerated recording paper is reusableor not utilizing a relationship between a residual amount of a toner andthe output of a photosensor shown in FIG. 3, drive a conveying pathswitching pawl 4B2 by turning a changeover switch 4B3 (for example, asolenoid type switch), via the interface 8B and a driving circuit 4B 3a,based on the judgement to convey the treated paper to each of thecompartments by a conveyor belt 4B1, convey the reusable paper through aconveyor path 9A into 9A1 and, if necessary, supply the same as it is toa printing apparatus.

Alternatively, it is also possible to supply the reusable recordingpaper directly to a printing apparatus without storing in 9A1. The paperjudged to be not reusable is conveyed through 9B into 9B1 and thendiscarded properly.

Assuming a recording paper conveying distance from the detecting element4A placed upstream of the conveyor belt 4B1 to the pawl 4B2 placeddownstream as “L” and a detection width of the element 4A as “B”, it ispreferable that the maximum length L_(o) and the maximum width B_(o) ofthe recording paper that can be treated in the present device has arelation: L>L_(o) and B>B_(o)

Further, the separation means 4 and thereafter will be explained morespecifically.

The separation means 4 is a section for discriminating to classifywhether the recording paper S come through the degrading treatmentsection in the regenerating treatment means 3 is reusable or not and itcomprises the printing density detecting element 4A, for example, aphotosensor, and the separating device 4B as shown in FIG. 1.

And said discrimination is carried out whether a detected output of theelement 4A for the recording paper S treated in 3 is higher than thestandard voltage determined according to the individual situation. Forexample, it is possible to determine the standard as a voltage valuecalculated by the equation:

(output of the photosensor corresponding to a reflecting light of asurface of the recording paper having no image thereon)×(predeterminedratio).

Further, FIG. 3 shows a graph taking a residual amount of toner on thepaper S on the axis of abscissa and an output of a photosenser to areflecting right on the axis of ordinal and the graph indicate that whenthe residual amount is much, the output is small.

The detecting element 4A described above is situated near the recordingpaper discharging section in the regenerating treatment means 3 fordetecting the density of the image on a surface of the recording paperS, which is connected to the control section 8 to be described later.Further, the element 4A is disposed so that the detection width (B) canbe made greater than the maximum width B_(o) of the recording paper S tobe regenerated and it is sometimes preferable to place a plurality ofthe element in parallel along the lateral direction or to make theelement reciprocated in the lateral direction.

Then, the separating apparatus 4B described above comprises a conveyorbelt 4B1 for conveying the recording paper S after passing the element4A, a conveying path switching pawl 4B2 which can swing situated at theend of 4B1 and a change-over switch 4B3 for swinging the pawl 4B2. Thepawl 4B2 is disposed at a position where a first discharging channel 9Afor supplying the reusable recording paper and a second dischargingchannel 9B for supplying the not reusable recording paper are branchedfrom each other and the pawl is usually set to a state capable oftransferring the recording paper S toward the first discharging channel9A.

The trays 9A1 and 9B1 are disposed to the ends of the first and thesecond discharging channels 9A and 9B.

On the other hand, as shown in FIG. 2, the control section 8 describedabove comprises the microcomputer 8A as a main part and it is connectedby way of the I/O interface 8B to external equipments.

The element 4A is connected to the input of the interface 8B, while thechange-over switch 4B3 provided to the separating device 4B is connectedby way of the driving circuit 4B3a to the output of the I/O interface 8Brespectively.

It is adapted in the control section 8 so that the amount of theresidual toner on the recording paper S is detected based on arelationship between the amount of light from the recording paper S andthe output from the element 4A obtained by the amount of light as shownin FIG. 3, and the state of elimination of the toner on the recordingpaper S is judged.

Further, it is also adapted so that the end of the detection of therecording paper S by 4A is detected also by the abrupt change of thedetection output, specifically, the time at which an outputcorresponding to the amount of light from the non-image area of S or toa calculated output which is set while considering contamination of thearea is obtained. The detection is used for setting the time for closingand opening the inside of the print degrading treatment means 3.

Namely, the concentration detected output by the photosensor 4A is putinto the microcomputer 8A in the control section 8 in FIG. 2 and theoutput is judged by 8A whether it is more than a predetermined value.When 8a judged that the output is more than the predetermined value andthe printed image on the paper S is sufficiently degraded, 8a maintainsthe driving circuit 4B4 in a normal state and set solenoid 4B3 and pawl4B2 in the separating section 4 in a normal position and a recordingpaper S which is judged reusable goes into the tray 9A1 through thefirst discharging channel 9A.

On the other hand, when the output of 4A is less than the predeterminedvalue, an electric output works on solenoid 4B3, through driving circuit4B4 and a position is set to send a recording paper S to the seconddischarging channel 9B. The fact that the detected output is less thanthe predetermined value means that the print degrading treatment is notenough or the paper is printed by a toner using a component which isundegradable by the device. Therefore, in this case, the paper S is sentto the tray 9B1 which is disposed at the end of the second dischargingchannel 9B by swinging the pawl 4B2.

Further, a waste bank, such as shredder, can be placed instead of 9B1 atthe end of 9B. If the shredder is designed to work only when the pawl4B2 is in a position shown by a dotted line, a disposal of a secretdocument can be done without being seen by others.

Further, instead of the tray 9A1, if the end of the first dischargingchannel is connected to the paper feeding section of a printingapparatus, it is preferable when it is necessary to feed the reusableregenerated recording paper to a printing apparatus.

Further, FIG. 4 shows a modified type to that shown in FIG. 1, that is,a regeneration device comprising a paper feed means 1B, a regeneratingtreatment means 1C, the content of which is to be described later, aseparating means 1E for separating the treated paper into reusablepaper, not-reusable paper and the paper to be put to regeneratingtreatment again and a storage means 1D to stored the treated paper.

The recording paper regeneration device shown in FIG. 4 comprises ahousing 1A and a paper feeding section 1B disposed on one of the wallsthereof for keeping recording paper S after copying with a printingapparatus, such as a copying machine, and becoming a waste.

The paper feeding means 1B comprises a recording paper storage cassette1B1, a delivery roller 1B2 which can be selectively in contact with orapart from the top end of the recording paper S in the cassette 1B1 anda feed roller 1B3, so that the recording paper S in the cassette 1B1 isdelivered and supplied toward the regenerating treatment means 1C to bedescribed later.

The regenerated paper storage means 1D has a reusable recording paperstacker 1D1 for storing reusable recording paper and a disposal tank 1D2for storing not reusable recording paper among the recording paper Sdischarged from the regenerating treatment means 1C, and a shredder 1D3is disposed at an inlet of the disposal tank 1D2 for shredding theintroduced not-reusable recording paper.

Accordingly, the conveying path 1E1 for a paper discharging side of theregenerating treatment means 1C is branched into a conveying path 1E1leading to the reusable recording paper stacker 1D1 and conveying path1E2 leading to the disposal tank 1D2, and a swingable first conveyingpath switching pawl 1E1a is disposed at the junction. The swinging stateof the first conveying path switching pawl 1E1a is set by a solenoid1E1b under driving control by a control section 8 to be described laterand it is set, as a normal state, i.e., as an initial state, so as tointroduce the recording paper for example into 1D2.

Further, the conveying path 1E1 is further branched behind the conveyingpath switching pawl 1E1a and one is extended to the reusable recordingpaper stacker 1D1 and the other is extended to the paper feeding means1B described before.

The reusable recording paper stacker 1D1 is not necessarily be limitedto one. It is sometimes preferable to have a plural number of thestacker 1D1 and storage reusable recording papers, for example,separating them size by size.

Therefore, a second conveying path switching pawl 1E2a is also disposedat the junction of the conveying path situated behind the first conveyorpath switching pawl 1E1a, and the swinging state of the pawl 1E2a is setby a solenoid 1E2b under driving control by a control section 8 to bedescribed later and it is set, as a normal state, i.e. an initial state,so as to introduce the recording paper S, for example, to the paperfeeding means 1B. In FIG. 4, the reference 1E4 denotes feed rollersdisposed in the conveying path as well as the path to 1B.

On the other hand, as shown in FIG. 5, the control section 8 comprises amicrocomputer 8A as a main part and it is connected by way of an I/Ointerface 8B to external equipments.

That is, the I/O interface 8B is connected, at its input, with thedensity detecting elements, for example, reflection type photosensors, 3and 4 for the detection of printing density disposed at a positionintroducing the recording paper from the paper feeding means 1B to theregenerating treating means 1C, and on the discharging side of therecording paper from 1C in the separating means 1E respectively and, atits output, with a driving circuit 1E1c for the solenoid 1E1b for thefirst conveying path switching pawl 1E1a and a driving circuit 1E2c forthe solenoid 1E2b for the second conveying path switching pawl 1E2a.

As shown in FIG. 6a, the photosensors 3 and 4 are designed to move inperpendicular to the conveying direction (St) of the recording paper Sso that they can scan a considerable range of area along the lateraldirection and the longitudinal direction of the recording paper S asshown by the broken line in FIG. 6b. The relation between the outputfrom the photosensors 3 and 4 and the density, that is, the amount ofthe residual toner is as shown in FIG. 3, in which it is indicated thatthe sensor output due to the amount of reflection light is reduced asthe residual amount of the toners increased.

Then, in the control section 8 described above, the print density (D₁)before the regeneration and the print density (D₂) after theregeneration on the printed surface of the recording paper S detected byeach of the photosensors 3 and 4 are inputted. Then, if the followingrelation is satisfied:

D₁−D₂≦0  (1)

the first conveying path switching pawl 1E1a is kept at the initialstate by not driving the driving circuit 1E1c for the solenoid 1E1b.Accordingly, the recording paper S discharged from the regeneratingtreatment means 1C is fed through the conveying path 1E1 by way of 1E3to the disposal tank 1D2.

On the other hand, if each of the above-mentioned densities satisfiesthe following relation:

D₁−D₂>0  (2)

the first conveying switching pawl 1E1a is swung from the initial stateby driving the driving circuit 1E1c for the solenoid 1E1b. Accordingly,the recording paper S discharged from the regenerating treatment means1C is conveyed passing through the conveying path 1E1 to a position forthe second conveying path switching pawl 1E2a.

When the first conveying path switching pawl 1E1a is set to the swungstate and, if the density (D₂) on the regenerated surface of therecording paper after the regeneration is in the following relationshiprelative to the standard density (D₀) which is a standard to judge thepaper is usable or not [for example background density (having no image)of the recording paper]:

D ₀−D₂≧0  (3)

it is judged that the density of the recording paper after theregeneration is a density capable of reusing and the second conveyingpath switching pawl 1E2a is swung from the initial state by driving thedriving circuit 1E2c for the solenoid 1E2b. Accordingly, the recordingpaper S is fed to the reusable recording paper stacker 1D1.

On the other hand, when the relation (3) above is not satisfied, it isjudged that erasion of a printed portion of the paper is not enough byone treatment although the regeneration has been done to some extent,and the second conveying path switching pawl 1E2a is maintained at theinitial state by not driving the driving circuit 1E2c for the solenoid1E2b. Accordingly, the recording paper S is fed to the paper feedingmeans 1B and then undergoes the regeneration again.

The background density used as the standard density as described aboveis preferably determined actually as follow:

D _(o)=D_(MIN)+D_(o)′

relative to the background density (D_(MIN)) of the recording paper notyet printed while taking the density (D_(o)′) caused by thecontamination due to remaining toner in the fibers of the recordingpaper S into consideration.

This embodiment has been constituted as described above, and descriptionwill be made to the state of conveying the recording paper based on theoperation of the control section 8 shown in the flow chart FIG. 7a.

When the recording paper S is fed from the paper feeding means 1B to theregenerating treatment means 1C, the density on the printed surface ofthe recording paper S is detected before it is introduced into theregenerating treatment means 1C by the photo sensor 3, and the detectiondata is put into the memory portion of the control section 8.

Then, the density of the recording paper S discharged after theregeneration is detected by the photosensor 4, and the detection data isput into the memory portion described above, for which the relationshown by the equations (1)-(3) is judged. Then, according to thejudgment, the feeding paths to the reusable recording paper stacker 1D1,the discarding tank 1D2 and the paper feeding means 1B are set bysetting the state of the first conveying path switching pawl 1E1a andthe second conveying path switching pawl 1E2a.

In the constitution described above, the photosensors for detecting thedensity of the recording paper are disposed on the side of introducingand discharging the recording paper to and from the regeneratingtreatment section.

However, in FIG. 4, by disposing the paper feeding means 1B and theseparating means 1E on the same side of the regenerating treatment means1C, it is possible to reduce two density detecting elements to one andto make the conveying path 1E4 shorter and these arrangements aresometimes preferable.

FIG. 8 and succeeding figures show detailed description of theregenerating treatment means (3 in FIG. 3 and 1C in FIG. 4).

FIG. 8 and FIG. 9 show means for regenerating recording paper printed byusing a toner comprising a biodegradable plastic as a constituentingredient, and FIG. 8 shows a print degrading section 3A and a dryingsection 3B, while FIG. 9 shows a cleaning section 3C.

The print degrading section 3A is a section for destroying the propertyof the toner composed of a biodegradable plastic and eliminatingfunctions required for the toner including so-called fixing anddepositing property or the like and it comprises, as shown in FIG. 8, atightly closed space formed with openings 3A1 and 3A2 at the introducingand discharging ports for the recording paper S and comprises adegrading agent storage tank 3A3 for storing a degrading agentcontaining microorganisms or enzymes for degrading the toner, adegrading agent coating device 3A4 and a conveyor belt 3A5.

The degrading agent coating device 3A4 comprises a felt materialextended between the degrading agent storing tank 3A3 and the conveyorbelt 3A5 and is so adapted to coat the degrading agent in contact withthe image surface of the recording paper S while being conveyed. Thedegrading agent coating device 3A4 may use a brush instead of the feltmaterial and, further, it may have a structure being capable of incontact with or apart from the recording paper S.

The conveyor belt 3A5 is laid around the driving pulley 3A6 and thedriven pulley 3A7, so that it can be moved in the direction of an arrowshown in the figure on the side carrying the recording paper S when thedriving pulley 3A6 is driven by a driving motor not shown in the figure.Further, the conveying speed of the conveyor belt 3A5 can be set to sucha level as capable of obtaining a time optimal to the degradingtreatment.

There are, further, disposed a temperature/humidity sensor 3A8 above theintroduction side of the recording paper S, an ultrasonic humidifier 3A9behind the sensor 3A8 in the conveying direction of the recording paperS and a ceramic heater 3A10 in a circle made by the conveyor belt 3A5having the recording paper S thereon at the inside of the degradingsection 3A respectively, so that the temperature and the humidity in thedegrading section 3A are maintained at a level to promote thebiodegradation of the toner.

On the other hand, the drying section 3B comprises a tightly closedspace formed with openings on the sides of introducing and dischargingthe recording paper S like those of the degrading section 3A and aconveyor belt 3B1 extended in the conveying direction of the recordingpaper S, a heater 3B2 and a blower 3B3 situated thereabove are disposedin the section 3B. In this embodiment, an infrared lamp heater is usedas the heater 3B2 by which the degrading agent coated on the recordingpaper S is dried, and steams formed by the drying are sucked by theblower 3B3 and discharged to the outside by way of a duct 3B4 in whichthe blower 3B3 is contained.

The duct 3B4 can be connected, if necessary, with a steam processingsection and, in this case, only the air, not containing the degradingagent and/or products thereof, is discharged to the outside of theregeneration device.

The cleaning section 3C is a portion for removing the toner set free onthe recording paper S by the degradation and drying and it comprises,for example, as shown in FIG. 9, a toner removing member 3C1 that can bein contact with the image surface of the recording paper S in a tightlyclosed space constituted with a box opened partially at the lowersurface, an ultrasonic vibrator 3C2 opposed to the toner removing member3C1 on both sides of the recording paper S, a cleaning member 3C3 suchas a blade or scraper abutting against the circumferential surface ofthe toner removing member 3C1 and a toner recovery member 3C4.

In this example, a rotary brush is used as the toner removing member 3C1to wipe off the toner on the recording paper S. Further, the cleaningmember 3C3 abuts against the top end of the brush of the toner removingmember 3C1 for wiping off the toner deposited to the brush. Further, thetoner recovery member 3C4 comprises a paddle wheel in this example fortransferring the fallen toner from the fallen position to otherpositions. The toner recovery member 3C4 is not restricted only to thepuddle wheel but it may be, for example, a screw member for transferringthe toner.

Further, in the cleaning section 3C, to provide the ultrasonic vibrator3C2, the conveyor belt for conveying the recording paper S is dividedinto two parts in a direction of the conveying on both sides of thevibrator 3C2.

In the regenerating treatment means 3 having the constitution asdescribed above, the recording paper S introduced into the printdegrading treatment section 3A receives the supply of the degradingagent by the degrading agent coating device 3A2, to undergo thebiodegradation of the toner and is dried in the drying section 3B uponcompletion of the degradation, and the toner degraded and set free fromthe surface of the recording paper is removed in the cleaning section3C.

The recording paper carrying, on its surface, a toner comprisingbiodegradable plastics as the constituent ingredient is introduced intothe print degrading treatment section 3A, and the treating ingredientsused in this example in the section 3A comprises:

degrading enzyme: Lysoverbs Telemer Lipase (manufactured by SeikagakuKogyo Co.: Trade name, Lysobspilase).

pH buffer for promotion of degradation: phosphate buffer solution.

In the print degrading treatment section 3A in the regeneratingtreatment means, temperature is set by the ceramic heater 3A10 forpromoting the biodegradation. Specifically, the temperature iscontrolled to about 37° C. and humidity is set by the ultrasonichumidifier 3A9 for preventing the drying on the surface of the recordingpaper at that temperature. The temperature and the humidity arecontrolled by the temperature/humidity sensor 3A8. Further, thetemperature setting as described above is not always required forbiodegradation as the degradation is possible even at a normaltemperature. However, it is preferable to set a temperature to apredetermined level with an aim of easy control for the degrading rateand time.

When the recording paper S is introduced into the print degradingtreatment section 3A, the section 3A put under such circumstantialsetting, the ports for introducing and discharging the recording paperin the section 3A are closed tightly and, thereafter, the degradingenzyme is coated on the recorded paper S by way of the degrading agentcoating member 3A4, and the conveying time is set by the speed of theconveyor belt 3A5 to degrade the toner.

Further, the recording paper S, the toner at the surface thereof beingdegraded in the conveying period as described above is discharged fromthe opening on the discharging side of the recording paper in the printdegrading treatment section 3A and conveyed to the drying section 3B.

In the drying section 3B, the openings for introducing and dischargingsides are closed tightly after the introduction of the recording paperS, the far-infrared heater 3B2 is lit and drying is carried out whiledetermining the conveying time by the conveyor belt 3B1 and then therecording paper S is conveyed to the cleaning section 3C by opening theport on the discharging side.

In the cleaning section 3C, the toner remaining on the recording paperafter degradation is set free by the ultrasonic vibrator 3C2 and thetoner in this state is wiped off by the toner removing member 3C1 andthen removed from the surface of the recording paper S.

On the other hand, the toner deposited to the toner removing member 3C1is scraped off from the member 3C1 by the cleaning member 3C3 and thenrecovered by the toner recovery member 3C4.

The recording paper S conveyed through the print degrading treatmentsection 3A, the drying section 3B and the cleaning section 3C isdischarged from the cleaning section 3C and detected for the density atthe treated image surface, for example, with the density detectingelement 4A shown in FIG. 1 and then sent to the separating means and thestorage means.

FIG. 10 shows a regenerating treatment means for regenerating therecording paper S printed by using the toner comprising thephotodegradable plastics, it comprises a print degrading treatmentsection 3A and a cleaning section 3C from the upstream to the downstreamin the conveying direction of the paper S.

The print degrading treatment section 3A is used for destroying theproperty of the toner composed of a photodegradable plastics andeliminating the function of the fixing and depositing property or thelike required for the toner, and it comprises, as shown in FIG. 10, atightly closed space formed with ports 3A1 and 3A2 at the introducingand discharging places of the recording paper S and it further comprisesa light irradiation member 3A11 and the conveyor belt 3A5.

For the light irradiation member 3A11, a lamp such as a xenon lamp,mercury lamp, LED or a lamp using laser beam which irradiates a raycontaining short wavelength light.

Then, the light irradiation member 3A11 starts lighting in timing with astarting of supply of the recording paper S detected by a detectingmember not shown in the figure and irradiates the entire surface of therecording paper S situated in the print degrading treatment section 3A.Further, the conveyor belt 3A5 is laid around the driving pulley 3A6 andthe driven pulley 3A7 so that the belt on the side carrying therecording paper S moves in the conveying direction of the recordingpaper S when the pulley 3A6 is driven by a driving motor not shown inthe figure and the belt 3A5, i.e., the paper S, can stay stationaryduring irradiation of light from the member 3A11. The conveyor belt 3A5is so adapted that it moves intermittently at a required time intervalfor the degradation or moves being switched to a lower speed when theentire irradiation can not be applied by the section 3A or partialdegradation is applied.

Accordingly, the recording paper S introduced into the section 3A movesin accordance with the setting for the moving speed or the moving stateof the conveyor belt 3A5 and can undergo the photodegradation by thelight irradiation member 3A11.

In this example, the recording paper S carrying, on its surface, a tonerusing the photodegradable plastics is introduced into the printdegrading treatment section 3A, in which a mercury lamp is used as thelight irradiation member 3A11, to irradiate light of a short wavelength.

Then, in the print degrading treatment section 3A althoughphotodegradation can be carried out under a normal temperature, sincethe reaction rate depends on the temperature, it may also be preferablethat temperature control is applied, for example, by placing a ceramicheater 3A10 at the back side of the belt 3A5 carrying the paper Sthereon to facilitate the stabilization of the degrading rate andcontrol of the degrading time.

Accordingly, when the recording paper S is introduced into the printdegrading treatment section 3A put under such a circumstantial setting,ports for the sides of introducing and discharging the recording paper Sin the section 3A are closed tightly and, thereafter, light of a shortwavelength is irradiated from the light irradiation member 3A11 andtoner is degraded for a period of the conveying time which is setdepending on the speed of the conveyor belt 3A5.

Further, the recording paper S having the toner on the surface thereofand being decomposed during the conveying period described above isdischarged through the port on the side of discharging of the printdegrading treatment section 3A and then conveyed to the cleaning section3C.

The cleaning section 3C has the same constitution as the section 3Cshown in FIG. 9, and the recording paper S is treated in the same manneras explained previously.

FIG. 11 shows a regenerating treatment means for eliminating the imageson the recording paper printed by using a toner or ink (hereinafterreferred to as the toner or the like) comprising an electron acceptingor electron donating color-forming organic compound and a developertherefor as a coloring material by using a color-eliminating agent andit comprises a print degrading treatment section 5A and a drying section5B from the upstream to the downstream of the conveying direction of therecording paper S.

Namely, the print degrading treatment section 5A is used for eliminatingthe color of the toner or the like comprising an electron acceptingcolor-forming organic compound or an electron donating color-formingorganic compound and a developer therefor and, as shown in FIG. 11, itcomprises a color eliminating agent tank 5A1 containing the agent forthe toner or the like, a color eliminating agent coating apparatus 5A2and a color eliminating agent recovery apparatus 5A3.

The color eliminating agent coating apparatus 5A2 has a structure ofsupplying the color eliminating agent to be described later to theentire printed surface of the recording paper and, specifically, itcomprises a coating roller 5A5, made of a rigid material such as metalor an elastic material such as rubber, which rotates and is situatedbetween a coating felt 5A4 incorporated in the color eliminating agenttank 5A1 and the conveying path for the recording paper S, and the coloreliminating agent is coated by the roller 5A5 receiving the supply ofthe color eliminating agent via the coating felt 5A4 incorporated intothe tank 5A1 and the roller 5A5 is in contact with the image surface ofthe recording paper S under conveying. The coating roller 5A5 rotatesreceiving the driving force of the driving motor 5A5a.

Further, the color-eliminating agent recovery apparatus 5A3 is so madethat it can be in contact with the color-eliminating agent coatingapparatus 5A2 having the recording paper S therebetween and it comprisesa driven roller 5A6 made of a rigid material such as metal or an elasticmaterial such as rubber, a scraper 5A7 abutting to the circumferentialsurface of the driven roller 5A6 and a recovery tank 5A8 having theroller 5A6 and the scraper 5A7 therein, and recovers thecolor-eliminating agent remaining on the circumferential surface of thecolor-eliminating agent coating apparatus 5A2 when the recording paperis not present between 5A5 and 5A6.

On the other hand, the drying section 5B comprises a conveyor belt 5B1and heaters 5B2 and 5B3 placed vertically on opposite sides of theconveyor belt 5B1 on the side carrying the recording paper, and it driesthe recording paper S after being supplied the color-eliminating agentin the print degrading treatment section 5A, the heater 5B2 situatedbelow the recording paper S has a function of drying the recording paperS and, accordingly, it is preferred to use the conveyor belt 5B1 made ofhighly heat conductive material. Further, in addition to the heater 5B2,the heater 5B3 situated above the recording paper S is used forpromoting the drying of the recording paper S in cooperation with theheater 5B2 and keeping it in a reusable state while preventing theoccurrence of curl or the like. Since this example is constituted asdescribed above, a recording paper having a printing portion formed withan electrophotographic toner containing an electron acceptingcolor-forming organic compound or an electron donating color-formingorganic compound and a developer in a printing device such as a copyingmachine is conveyed from the paper feed means 2 to the regeneratingtreatment means 3 as shown in FIG. 1.

Then, in the regenerating treating means 3, the color-eliminatingreaction is caused in the print degrading treatment section 5A bycoating the color-eliminating agent by the coating apparatus 5A2 in thesection 5A of FIG. 11. The color-eliminating reaction is substantiallycompleted just after the coating of the agent and the printed surface ofthe recording paper S is whitened. Then, in this state, the recordingpaper S is conveyed to the drying section 5B and is then dischargedafter evaporation of the remaining color-eliminating agent and thenenters into the separating means 4 shown in FIG. 1.

According to this example, since the color-eliminating reaction iscompleted shortly after coating the color-eliminating agent, it ispossible for this color-eliminating regeneration that a great amount ofprinting surface can be treated in a short period of time and, since theregeneration is completed substantially in an identical time as that ofthe printing speed on the side of the printing apparatus such as acopying machine, it can provide an effective response capable of rapidlycoping with a case resulting in shortcoming of the recording paper on aside of the printing.

On the other hand, in the constitution described above as the example,the color-eliminating agent is supplied to the entire region of theprinted surface of the recording paper S, but it may alternatively beadapted so that the color-eliminating agent is supplied only to alimited portion of the printing surface, that is, only to a portionactually deposited with the toner and a like taking consideration forthe shortening of the drying time.

FIG. 12 is a constitutional example as described above, in which thecolor-eliminating agent is supplied by a spray head.

The structure shown in FIG. 12 comprises a position detecting section 6for detecting the toner deposited position on the printed surface of therecording paper and a print degrading treatment section 7.

The position detecting section 6 has a charge coupling device (CCD) 6Aextended in the lateral direction of the recording paper S as the mainportion and detects the position of the toner deposited on the printedsurface of the recording paper S under conveyance as the coordinateposition and, further, the amount of the deposited toner as the density.Detection by the charge coupled device 6A is started corresponding tothe detection for the top end of the recording paper S by the reflectiontype photosensor 6B situated at the upstream in the conveying directionof the recording paper S.

Further, the recording paper S passing through the position detectingsection 6 is turned its conveying path from a horizontal direction to avertical direction by a guide plate 7D1 and opposes to the printdegrading treatment section 7 at the position in the vertical direction.

The print degrading treatment section 7 comprises a spray head 7Acapable of moving in the lateral direction of the recording paper S. Thespray head 7A is slidable, for example, along two rods 7A1 in parallelwith each other in the lateral direction of the recording paper S, andthe movement on the rods 7A1 is carried out by an endless belt 7A3having turn-back portions at pulleys 7A2 situated on both ends of thelateral direction and being secured at the both lateral ends of thesurface of the spray head 7A and by a driving motor 7A4 by way of adriving pulley 7A2 situated at one of the turn back portions of theendless belt 7A3. The driving motor 7A4 is controlled by a signal from acontrol section 8 to be described later.

The spray head 7A has a jetting port opposed to the printed surface ofthe recording paper S of which conveying direction is converted into avertical direction and it can jet out a color-eliminating agent insteadof an ink having the same structure as an ink jet device of a well-knownstructure including, for example, a structure using a mechanicalprinciple of jetting out an ink while changing the pressure in an inkchamber by a Vibrator or using a physical principle of extractingthrough a grid the ink jetted out by the vibrator or by means of anelectrostatic force. In the drawing, references 6C and 7C representpinch rollers respectively. Further, reference 7A5 represents acolor-eliminating agent tank and it can incorporate, for example, a pumpfor charging the color-eliminating agent to the head in the tank 7A5.

The time for jetting the color-eliminating agent from the spray head 7Ais set by a driving signal from a control section 8 based on thepositional information detected by the charge coupled device 6A in theposition detecting section 6.

That is, the control section 8 is adapted to intake the toner depositedposition on the coordinate and the toner deposited amount detected bythe charge coupled device 6A starting the operation from the instancethe top end of the recording paper is detected by the photosensor 6B inthe position detecting section 6, takes the intook information into amemory portion and, referring to the conveying speed of the recordingpaper S in the print degrading treatment section 7, based on theinformation, determines the jetting time based on a position of theinstance a top end of the recording paper detected by the photosensor7B, gives a driving instruction for jetting the color-eliminating agentwhen the head 7A is opposed to a portion having the toner and the likeon a printed surface of the recording paper and drive the chargingequipment for the color-eliminating agent, for example, a pump.

A guide plate 7D2 is disposed at a position subsequent to the passage ofthe recording paper S before the spray head 7A to convert the conveyingpath of the recording paper S from a vertical direction to a horizontaldirection, and the paper S, changing its direction accordingly isconveyed with the conveyor belt 7E and then discharged through thedrying section to the separating means 4.

Since this example is constituted as described above, the mode forsupplying the color-eliminating agent can be controlled, and the amountof the agent required for color-elimination can be set by judging thestate of the toner deposited to the printed surface of the recordingpaper and the maximum color-eliminating effect can be obtained by theminimum amount of the agent and this leads to the reduction of the costfor obtaining the regenerated recording paper.

In the structure described above, the spray head is disposed opposing toone side of the recording paper S but it is not restricted only theretoand it is also possible to conduct color-elimination of the recordingpaper printed on both surfaces thereof by disposing the spray heads onboth surfaces of the recording paper.

In accordance with the method of the present invention, the color can beeliminated only for the restricted portion on the printed surface bypartially modifying the position detecting section 6 and the controlsection 8. For instance, when the color is eliminated only for thespecified lines on the printed surface and corrected lines are printedthere, the printed recording paper, which would otherwise be obliged tobe discarded can be reused.

Further, the printing density detecting element 3 in FIG. 4 may bereplaced with a reading device and the printed surface before theregeneration is displayed on a display provided in a control section 8to indicate a portion to be eliminated by eyes using a display pointingapparatus such as an arrow by a light pen, mouse, button or the like andgive the indication through the control section to the regeneratingsection. Although the foregoing descriptions have been made to a methodof partially eliminating the image of a toner or the like comprising theelectron donating or electron accepting color-forming organic compoundand the developer, the regeneration can be attained by the identicalprinciple also by a combination of a toner comprising a photodegradableplastics as the constituent ingredient and an irradiation device for alaser beam or a light beam, or the like, or a toner comprisingbiodegradable plastics as the constituent ingredient and a jet spray ofa degrading agent therefor.

The above description can also be explained by a block diagram shown inFIG. 7b. The printed recording paper S is supplied by the paper feedingmeans 1B shown in FIG. 4 and an image thereon is read with a printedpaper reader before the regenerating treatment and the image isdisplayed on a display apparatus disposed in the control section 8. Arange, to be eliminated, of the image on the display apparatus isdetermined by a display pointing apparatus using, for instance, a lightpen, mouse or button. The range is input to the controller in thesection 8 and it instructs the spray head or a beam irradiation deviceto move accordingly and the determined range of the image on the paper Sis eliminated.

Although the feature of the present invention has been described withreference to the drawings, the drawings are used only for making thecontents of the present invention more concretely, more clearly andeasily to be understood and the present invention is no way limited onlyto those illustrated in such drawings. For instance, what is illustratedas the photosensor is not necessarily restricted to the photosensor, solong as it can detect the concentration on the printed surface. Further,the conveyor belt illustrated as the conveying device is not necessarilybe a conveyor belt so long as it can convey the recording paper as itis. Furthermore, any of drying methods may be used providing that it candry a liquid remaining on the treated surface of the recording paper.The foregoings are only a part of examples and other modifications willbe apparent per se from the above-mentioned examples.

The toner referred to in the present invention is a finely powderouscoloring pigment used for electrography capable of providingchargeability and the toner generally comprises (1) a binder resin, (2)a coring material, (3) a charge controller and (4) a carrier.

(1) For the resin binder, there can be mentioned: homopolymer orcopolymer containing styrene or substituted styrene such as polystyrene,chloropolystyrene, poly-α-methylstyrene, styrene-chlorostyrenecopolymer, styrene-propylene copolymer, styrene-butadiene copolymer,styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymerstyrene-maleic acid copolymer, styrene-acrylic acid ester copolymer (forexample, styrene-methylacrylate copolymer, styrene-ethylacrylatecopolymer, styrene-butylacrylate copolymer, styrene-phenylacrylatecopolymer), styrene-α-methyl chloroacrylate copolymer,styrene-acrylonitrile-acrylate copolymer; vinyl chloride resin, rosinmodified maleic acid resin; phenolic resin; epoxy resin; polyesterresin; low molecular weight polyethylene; low molecular weightpolypropylene; ionomer resin; polyurethane resin; ketone resin;ethylene-ethylene acrylate copolymer; xylene resin; and polybutylbutyralcan be exemplified.

(2) As the coloring material, carbon black is most popular and there canbe mentioned various other materials such as yellow, red or blue/greencolor materials. The coloring material is used usually by 0.5 to 40parts by weight based on 100 parts by weight of the binder resin.

(3) As the charge controller, there can be used negative material suchas metal complex salt dye, metal salicylate, metal salt of salicylicacid derivative, and positive material such as nigrosine dye, quaternaryammonium salt and amino acid-containing resin. The charge controller isusually used from 0.05 to 25 parts by weight based on 100 parts byweight of the binder resin.

(4) As the carrier, there can be mentioned, for example, iron oxidepowder, Ni—Zn ferrite, Cu—Zn ferrite, Be ferrite, Sr ferrite, ZnOferrite, glass beads, iron powder, Ni powder, Cu powder, and resin beadsand the carrier having a diameter of 10 to 300 μm are usually used.

Recording paper printed with a toner prepared by adding a degradableplastics to the above-mentioned constitutions is one of the targets forregenerating in the regeneration device of the present invention usingdegradable plastic. The toner is only at the beginning of the use atpresent and those put to practical use include biodegradable plasticsand photodegradable plastics. Although descriptions are mainly made totwo kinds of them in the present specification, a recording paperprinted with a toner using other degradable component can also beregenerated with the regeneration device according to the presentinvention when the degradable component is combined with properdegrading agent.

As the biodegradable plastics, there can be mentioned those polymersclassified as polysaccharides and they include, specifically, Echosterand Echoster Plus manufactured by Hagiwara Kogyo and they are usuallyused from 1 to 70 parts by weight based on 100 parts by weight of thebinder resin.

As the degrading agent for the toner using biodegradable plastic, therecan be mentioned lipase and lipase effecting material. The lipaseincludes enzymatically decomposing lipase, as well as ester decomposingesterase, phospholipase and lysophoslipase, while the lipase effectingmaterial includes those having the same effect as lipase and there canbe exemplified crude lipase, lipase containing material, lipase yieldingbacteria and lipase yielding cultural product.

As the photodegradable plastic material, polymers of vinyl ketone typemonomers are used and they can include, methyl vinyl ketone, methylpropenyl ketone, t-butyl vinyl ketone, ethyl vinyl ketone, phenyl vinylketone, divinyl ketone, acetoxy methyl ketone, chloromethyl ketone,α-acetoxymethyl vinyl ketone, β-chlorovinyl methyl ketone andα-chlorovinyl methyl ketone as the monomer. The polymer of the suchvinyl type polymer may be a homopolymer or a copolymer and as the matingmonomer in the copolymer, there can be mentioned, for example, ethylene,styrene, methyl methacrylate, α-butyl methacrylate, α-ethylenehexylmethylacrylate, vinyl chloride, α-methylstyrene, acrylonitrile, vinylacetate and propylene. The plastic material is usually used from 1 to 70parts by weight based on 100 parts by weight of the binder resin.

Further, the following photodegradation promoter may be used dependingon the case. There can be mentioned, for example, aldol-α-naphthylaminecondensate, acetyl acetone, metal-iron-diethyldithiocarbamate, salicylaldehyde, α-mercaptobenzothiazole, metal salt of stearic acid,thiodipropionic acid, iron acetyl acetonate, p-benzoquinone,α-naphthoquinone, anthraquinone and derivatives thereof.

In the above-mentioned photodegradable plastics when constituted as atoner, since the ketone groups effectively absorb light energy under thelight irradiation to disconnect —C—C— bonds, the function of the tonersuch as fixing or depositing property is removed.

Accordingly, as the light source used for the light irradiation, thoseirradiating light of short wavelength of good adsorbability is preferredand there can be mentioned, for example, an irradiation device such as axenon lamp and a mercury lamp, as well as a device for short wavelengthlaser.

Further, as the printing toner on the printed recording paper that canbe regenerated by the regenerating device according to the presentinvention, there can be mentioned, for example, a toner comprising anelectron accepting color forming organic compound and a developer.

The electron accepting color-forming organic compound used hereinincludes those of colorless to pale color, including phthalane andfluorescene and, there can be exemplified the followings. That is,thymolphthalane, phenolphthalane, o-cresol-phthalane,1,4-dimethyl-5-hydroxybenzene sulfophthalene, m-cresol sulfophthalene,α-naphtholphthalene, o-cresol sulfophthalane, phenolsulfophthalane,fluorescene, sulfofluorescene, tetrabromofluorescene andtetrachlorofluorescene.

As the developer for the electron accepting color-forming organiccompound, there can be mentioned, for example, amine such as octylamine, lauryl amine, stearyl amine, dibutyl amine, tripropyl amine,dimethyl aniline, p-toluidine, β-naphthyl amine, pyridine, picoline,lutidine, quinoline, piperidine, imidazole, triazine and morpholine;quaternary ammonium salts such as tetraethyl ammonium and amino acidssuch as glycine and alanine.

A printing ink can be prepared in a conventional manner by using thecombination of the above-mentioned color forming organic compound andthe developer as the coloring material, a general toner can also beprepared in combination of the above compounds with the binder resin,charge controller and carrier described above.

Examples of the color-eliminating agent used for such toners and thelike can include, for example, alcohols such as n-octyl alcohol, n-nonylalcohol, n-lauryl alcohol, n-stearyl alcohol, cyclohexanol, benzylalcohol, cinnamyl alcohol, ethylene glycol, diethylene glycol,triethylene glycol, propylene glycol, trimethyl propane,pentaerylthritol, sorbitol and mannitol; esters such as octyl acetate,butyl propionate, ethyl laurate, ethyl benzoate, dimethyl phthalate,dioctyl phthalate and dicyclohexyl phthalate, ketones such asbenzophenone, methylcyclohexanone, acetonyl acetone and diacetonealcohol, ethers such as diphenyl ether, dioxane, ethylene glycol dibutylether and diethylene glycol dibutyl ether, acids amides such asacetoamides and propionic amide, a compound having a phenolic hydroxygroup or derivatives thereof and a compound having carboxyl group andderivatives thereof.

The compound having the phenolic hydroxy group and the derivativethereof can include from monophenols to polyphenols and metal saltsthereof and the substituents therefor can include alkyl group, arylgroup, acyl group, alkoxy carbonyl group and halogen group. Referringmore specifically to the compound, there can be mentioned, for example,nonyl phenol, styrenated phenol, α-naphthol, β-naphthol, hydroquinone,butyl p-oxybenzoate, 4,4-methylenediphenyl, bisphenol A, bisphenol S,octyl salicylate and phenol resin. As the metal salts thereof, there canbe mentioned, for example, metal salts of the compounds having thephenolic hydroxy group such as sodium, potassium, lithium, calcium,zinc, aluminum, nickel, cobalt, iron, titanium, lead and molybdenum.

Further, as the compound having the carboxyl group and derivativesthereof, there can be mentioned, for example, from monocarboxylic topolycarboxylic acids and substituent derivatives thereof and metal saltsthereof. Examples of such compounds include, for example, acetic acid,propionic acid, capronic acid, caprilic acid, lauric acid, mirysticacid, palmitic acid, stearic acid, behenic acid, 12-hydroxy stearicacid, benzoic acid, protocatechuic acid, salicylic acid, phthalic acid,naphthalene diacarboxylic acid, sebatic acid, naphthenic acid and citricacid.

The metal salts thereof can include such as sodium, potassium, lithium,calcium, zinc, aluminum, nickel, cobalt, iron, titanium, lead ormolybdenum salt of the carboxylic acids described above.

In the case of using the color-eliminating agent as a liquid, watersoluble material is diluted with water and a solvent soluble material isdiluted with an organic solvent such as alcohol, acetone or toluene atan optional ratio. Further, the liquid material may be blended withpolyvinyl pyrrolidone, ethylene glycol or glycerine so as to obtain anoptional viscosity.

Further, a recording paper printed with a toner comprising an electrondonating color-forming organic compound instead of the electronaccepting color forming organic compound and a developer therefor canalso be one object of the regeneration device according to the presentinvention.

Also for the electron donating color-forming organic compounds,colorless or pale colored materials are used and they are generallyclassified into diaryl phthalids, aryl phthalids, indolyl phthalids,leuco auramines, rhodamine lactams, spiropyranes, fluoranes,phenothiazines, triphenylmethanes, and aryl furanes and as the compoundtherefor, there can be mentioned, for example, crystal violet lactone,malachite green lacton, leuco auraminc, rhodamine B lactam,N-3,3-trimethylindolino benzapiropiran,3-diethylamino-6-methyl-7-chlorofluorane,3,6-di-p-toluidino-4,5-dimethylfluorane,3,3-bis(1-ethyl-2-methylindol-3-yl)phthalide, benzoyl leucomethyleneblue.

As the developer for the electron donating color forming organiccompound, there can be mentioned a compound having a phenolic hydroxygroup and a derivative thereof or a compound having a carboxyl group anda derivative thereof.

As the compound having the phenolic hydroxyl group and the derivativethereof, there can be mentioned, for example, from monophenols topolyphenols and the metallic salt thereof, and the substitutedcompounds, and the substituent thereof can include, for example, alkylgroup, aryl group, acyl group, alkoxycarbonyl group and halogen group.

Referring to the compounds, there can be mentioned, for example, nonylphenol, styrenated phenol, α-naphthol, β-naphthol, hydroquinone, butylp-oxybenzoate, 4,4-methylene diphenyl, bisphenol-A, bisphenol-S, octylsalicylate and phenol resin. As the metal salts thereof, there can bementioned metal salt of the compound having the phenolic hydroxy groupsuch as of sodium, potassium, lithium, calcium, zinc, aluminum, nickel,cobalt, iron, titanium, lead and molybdenum.

Further, as the compound having the carboxyl group and derivativesthereof, there can be mentioned, for example, from monocarboxylic topolycarboxylic acids and substituted derivatives and metal saltsthereof. As the compound there can be mentioned, for example, capronicacid, caprilic acid, lauric acid, mirystic acid, palmitic acid, stearicacid, behenic acid, 12-hydroxy stearic acid, benzoic acid,protocatechuic acid, salicyclic acid, phthalic acid, naphthalenediacarboxylic acid, sebatic acid and naphthenic acid. As the metal saltstherefor, there can be mentioned, for example, metal salts of thecarboxylic acid such as of sodium, potassium, lithium, calcium, zinc,aluminum, nickel, cobalt, iron, titanium, lead and molybdenum.

Usual ink or toner can also be prepared by using the combination of thecolor-forming organic compound and the developer as described above inthe same manner as the electron accepting color-forming organiccompound.

Examples of the color-eliminating agent used for the toner can include,for example, alcohols such as n-octyl alcohol, n-nonyl alcohol, n-laurylalcohol, n-stearyl alcohol, cyclohexanol, benzyl alcohol, cinnamylalcohol, ethylene glycol, triethylene glycol, propylene glycol,trimethyl propane, pentaerylthritol, sorbitol and mannitol; esters suchas octyl acetate, butyl propionate, ethyl laurate, ethyl benzoate,dimethyl phthalate, dioctyl phthalate and dicyclohexyl phthalate,ketones such as benzophenone, methylcyclohexanone, acetonitryl acetoneand diacetone alcohol, ethers such as diphenyl ether, dioxane, ethyleneglycol dibutyl ether, diethylene glycol dibutyl ether, ethylene glycoldiethyl ether and diethylene glycol diethyl ether; acid amides such asacetoamide and propionic amid, amines such as octyl amine, lauryl amine,stearyl amine, dibutyl amine, tripropyl amine, dimethyl aniline,p-toluidine, β-naphthyl amine, pyridine, picoline, lutidine, quinoline,piperidine, imidazole, triazine and morpholine; quaternary ammoniumsalts such as tetraethyl ammonium salt; and amino acids such as glycineand alanine.

What is claimed is:
 1. A device, connected to a regeneration device, forselectively separating recording medium, comprising: means fordiscriminating whether a regenerated recording medium is reusable; andmeans for selectively separating the regenerated recording medium intoreusable recording medium.
 2. A device, connected to a regeneratingdevice having a regenerating section, for selectively separatingregenerated recording medium, comprising: discriminating means connectedto said regenerating section for discriminating whether a regeneratedrecording medium is reusable; and separating means disposed on adownstream side of said discriminating means for selectively separatingthe regenerated recording medium into reusable recording medium and notreusable recording medium on the basis of the discrimination result ofsaid discriminating means.
 3. A device according to claim 1 or claim 2,which further includes means for storing the separated reusablerecording medium.
 4. A device according to claim 1 or claim 2, whereinthe separated recording medium being judged not reusable is conveyeddirectly to a destroying apparatus.
 5. A device according to claim 4,wherein said destroying apparatus is shredder.
 6. A device according toclaim 1 or claim 2, wherein said discriminating means and saidseparating means comprise: a print density detecting element fordetecting printed density of the regenerated recording medium; anapparatus for conveying the medium after the density detection; aconveying passage switching device for separating the treated recordingmedium into reusable and not reusable recording medium; and saiddetecting element being connected to the input of a control section andsaid switching device being connected to the output of said controlsection, comparing the result of the detection from said detectingelement and a standard print density and setting the position of saidswitching device in accordance with the result of the comparison.
 7. Adevice according to claim 1 or claim 2, wherein said discriminatingmeans and said separating means comprise: a print density detectingelement for the recording medium before a regeneration treatment; aprinted density detection element for the recording medium after theregeneration treatment; an apparatus for conveying the recording mediumto its destination after the detections of the densities; a plurality ofconveying path switching devices for separating the detected medium asreusable, not reusable and to be regenerated again; and a controlsection having said detecting and detection elements connected to theinput and said switching devices connected to the output, being made tocompare the results of the detection by both of the detecting anddetection elements and a standard print density and to set the positionof each of the switching devices according to the result compared.
 8. Adevice according to claim 6, wherein a conveying distance from theprinted density detection element for the recording medium afterregenerating treatment to the first conveying path switching device ismore than a maximum length of the recording medium to be treated and adetectable width of said detecting element is more than a maximum widthof the recording medium to be treated.
 9. A device according to claim 6,wherein the regenerated recording medium is judged to be not reusablewhen a printed density of the recording medium is higher than saidstandard density and judged to be reusable when the printed density islower than or equal to said standard density.
 10. A device according toclaim 6, wherein said standard density is a background density of therecording medium having no print.
 11. A device according to claim 6,wherein said print density detecting element is movable to a directionperpendicular to the conveying direction and parallel to a plane of therecording medium.
 12. A device according to claim 7, wherein a conveyingdistance from the printed density detection element for the recordingmedium after regenerating treatment to a first conveying path switchingdevice is more than a maximum length of the recording medium to betreated and a detectable width of said detecting element is more than amaximum width of the recording medium to be treated.
 13. A deviceaccording to claim 7, wherein said standard density is a backgrounddensity of the recording medium having no print.
 14. A device accordingto claim 7, wherein said print density detecting element is movable in adirection perpendicular to a conveying direction and parallel to a planeof the recording medium.
 15. The device of claim 1, wherein said meansfor discriminating discriminates three types of regenerated recordingmedium as follows: (1) reusable recording medium; (2) not reusablerecording medium; and (3) recording medium in need of furtherregeneration.
 16. The device of claim 15, further including means for:(1) feeding recording medium discriminated as reusable to one of areusable storage location and a printing location; (2) feeding recordingmedium discriminated as not reusable to one of a not reusable storagelocation and a shredding means; and (3) feeding recording mediumdiscriminated as in need of further regeneration to regenerating means.17. The device of claim 1, wherein said means for discriminatingincludes control means for determining an end of a discriminatingoperation to set a timing for opening and closing an outlet ofregeneration means disposed upstream of a location at which regeneratedrecording medium is discriminated.
 18. A method for erasing a printedimage formed on a recording medium, comprising the steps of: erasing theprinted image formed on the recording medium for regenerating therecording medium; detecting a residual image of the recording mediumregenerated by said erasing step; discriminating whether the regeneratedrecording medium is reusable or not reusable based on a detecting resultof said detecting step; and selectively separating the regeneratedrecording medium into a reusable recording medium.
 19. A methodaccording to claim 18, wherein said detecting step detects a residualimage density of the regenerated recording medium.
 20. A methodaccording to claim 18, wherein said discriminating step discriminatesthree types of the regenerated recording medium as a reusable recordingmedium, a not reusable recording medium, and a recording medium in needof further regeneration.
 21. A method according to claim 18, whereinsaid discriminating step discriminates a reusable recording medium fromanother recording medium.
 22. A method according to claim 18, whereinsaid discriminating step discriminates a reusable recording medium froma not reusable recording medium.
 23. A method according to claim 18,wherein said discriminating step discriminates a reusable recordingmedium from a recording medium in need of further regeneration.
 24. Amethod for erasing a printed image formed on a recording medium andregenerating the recording medium to be reusable, comprising the stepsof: erasing the printed image formed on the recording medium forregenerating the recording medium; detecting a regenerating result ofthe recording medium regenerated by said erasing step; and selectivelyseparating and storing the regenerated recording medium into a reusablerecording medium and a not reusable recording medium based on adetecting result of said detecting step.
 25. A system for erasing aprinted image formed on a recording medium and regenerating therecording medium, comprising: a regenerator which erases the printedimage formed on the recording medium; a detector disposed downstream ofthe regenerator in a recording medium moving direction, and whichdetects the regenerating result of the recording medium regenerated bythe regenerator; a discriminator which discriminates whether theregenerated recording medium is reusable or not reusable; and at leastone separator disposed downstream of the detector in the recordingmedium moving direction, and which separates the recording mediumdiscriminated by the discriminator into a reusable recording medium andanother recording medium.
 26. A system according to claim 25, whereinsaid detector detects a residual image density of the regeneratedrecording medium.
 27. A system according to claim 25, wherein saidseparator comprises a switching pawl.
 28. A system for erasing a printedimage formed on a recording medium and regenerating the recordingmedium, comprising: a regenerator which erases the printed image formedon the recording medium; a detector disposed downstream of theregenerator in a recording medium moving direction, and which detectswhether the recording medium regenerated by the regenerator is reusable,not reusable, or in need of a further regeneration process by theregenerator; at least one separator disposed downstream of the detectorin the recording medium moving direction, and which separates theregenerated recording medium into a reusable recording medium, a notreusable recording medium, and a recording medium in need of a furtherregeneration process by the regenerator on the basis of a detectionresult of the detector; and a conveyor which conveys the recordingmedium in need of a further regeneration process by the regeneratorseparated by said at least one separator to the regenerator.
 29. Asystem according to claim 28, wherein said detector detects a residualimage density of the regenerated recording medium.
 30. A systemaccording to claim 28, wherein said separator comprises a switchingpawl.
 31. A system according to either one of claim 25 or claim 28,further comprising a stocker which stocks respectively the reusablerecording medium and the not reusable recording medium separated by saidat least one separator.
 32. A regenerating system comprising: aregenerating section which erases a printed image formed on a recordingsheet; a residual image detecting device disposed downstream of theregenerating section in a recording sheet moving direction, and whichdetects a residual image remaining on the recording sheet after aregenerating process by said regenerating section; a controller whichcompares the residual image remaining on the recording sheet, withoutbeing erased after the regenerating process by said regeneratingsection, detected by said residual image detecting device with astandard image data, and which determines the recording sheet to bereusable or not reusable on the basis of the comparing result of theresidual image; a stocker which stocks the reusable recording sheet; anda conveying pass switch disposed downstream of the residual imagedetecting device in the recording sheet moving direction, and whichswitches the conveying direction of the recording sheet determined to bereusable based on the comparing result in said controller to a directionof the stocker.
 33. A system according to claim 32, wherein saidconveying pass switch further switches the conveying direction of therecording sheet determined to be in need of a further regenerationprocess by said regenerating section on the basis of the comparingresult in said controller to a direction of the regenerating section,and said regenerating section erases the residual image on the sheetdetermined to be in need of a further regeneration process by saidregenerating section on the basis of the comparing result in saidcontroller.
 34. A method for reusing a recording medium, comprising thesteps of: discriminating whether a regenerated recording medium isreusable; and selectively separating the regenerated recording mediuminto a reusable recording medium.
 35. A method according to claim 34,wherein said discriminating step discriminates three types of theregenerated recording medium as a reusable recording medium, a notreusable recording medium, and a recording medium in need of furtherregeneration.
 36. A method according to claim 34, wherein saiddiscriminating step discriminates a reusable recording medium fromanother recording medium.
 37. A method according to claim 34, where saiddiscriminating step discriminates a reusable recording medium from a notreusable recording medium.
 38. A method according to claim 34, wheresaid discriminating step discriminates a reusable recording medium froma recording medium in need of further regeneration.
 39. A method for aregeneration system having a regenerating section, for selectivelyseparating a regenerated recording medium, comprising the steps of:discriminating whether the regenerated recording medium is reusable; andselectively separating the regenerated recording medium into a reusablerecording medium and a not reusable recording medium on the basis of adiscrimination result of said step of discriminating.
 40. A system forerasing a printed image formed on a recording medium and regeneratingthe recording medium, comprising: a regenerating device which erases theprinted image formed on the recording medium; a discriminating devicedisposed downstream of the regenerating device in a recording mediummoving direction, and which discriminates whether the recording mediumregenerated by the regenerating device is reusable or not reusable; anda separating device which separates the recording medium discriminatedby the discriminating device into a reusable recording medium and a notreusable recording medium.
 41. A system for erasing a printed imageformed on a recording medium and regenerating the recording medium,comprising: a regenerating device which erases the printed image formedon the recording medium; a discriminating device disposed downstream ofthe regenerating device in a recording medium moving direction and whichdetects whether the recording medium regenerated by the regeneratingdevice is reusable, not reusable, or in need of a further regenerationprocess by the regenerating device; a separating device disposeddownstream of the discriminating device in the recording medium movingdirection, and which separates the recording medium into a reusablerecording medium, a not reusable recording medium, and a recordingmedium in need of a further regeneration process by the regeneratingdevice on the basis of the discrimination result of the discriminatingdevice; and a conveying device which conveys the recording medium inneed of a further regeneration process by the regenerating deviceseparated by said regenerating device to the regenerating device.
 42. Asystem according to either one of claim 40 or claim 41, furthercomprising a stocker which stocks respectively the reusable recordingmedium and the not reusable recording medium separated by saidseparating device.
 43. A regenerating system comprising: a regeneratingsection which erases a printed image formed on a recording sheet; adetecting element disposed downstream of the regenerating section in arecording sheet moving direction, and which detects a residual imageremaining on the recording sheet after a regenerating process by saidregenerating section; a control section which compares the residualimage remaining on the recording sheet, without being erased after theregenerating process by said regenerating section, detected by saiddetecting element with a standard image, and which determines therecording sheet to be reusable or not reusable based on a comparingresult of the residual image; a stocker which stocks the reusablerecording sheet; and a conveying pass switching section disposeddownstream of the detecting element in the recording sheet movingdirection, and which switches the conveying direction of the recordingsheet determined to be reusable based on the comparing result in saidcontrol section to a direction of the stocker.
 44. A system according toclaim 43, wherein said conveying pass switching section further switchesthe conveying direction of the recording sheet determined to be in needof a further regeneration process by said regenerating section on thebasis of the comparing result in said control section to a direction ofthe regenerating section, and said regenerating section erases theresidual image on the sheet determined to be in need of a furtherregeneration process by said regenerating section on the basis of thecomparing result in said control section.
 45. A system for erasing aprinted image formed on a recording medium and regenerating therecording medium, comprising: a regenerator which erases the printedimage formed on the recording medium; a detector disposed downstream ofthe regenerator in a recording medium moving direction, and whichdetects a regenerating result of the recording medium regenerated by theregenerator; a discriminator which discriminates whether the regeneratedrecording medium is reusable or not reusable; and a stocker disposeddownstream of the detector in the recording medium moving direction, andwhich stocks respectively the recording medium discriminated by thediscriminator into a reusable recording medium and a not reusablerecording medium.